This application claims the priority of German Patent Document No. 100 63 766.3, filed Dec. 21, 2000, the disclosure of which is hereby incorporated by reference.
The invention relates to an air bag system for a passenger car with at least one inflatable air bag.
Modern passenger cars already include air bag systems, in which an air bag is housed in the steering wheel or on the passenger side in the dashboard, to reduce the risk of injury in the event of a crash. Whereas a conventional air bag damps the frontal impact of the driver""s head or the passenger""s head, modern motor vehicles also have side air bags, which also damp the side impact of the head or the body. Such side air bags are housed, for example, in the so-called xe2x80x9cB pillarsxe2x80x9d or in the side checks of the backrests.
German Patent Document DE 195 47 494 A1 discloses an air bag system, in which an inflatable, hose-shaped air bag is housed in a channel below the side door shoulder. The rear end of the air bag is connected to an adjusting device, for example in the form of a push rod, which can be moved upwards in the event of impact, and which moves the air bag into a position that prevents the passenger""s head from moving to the side, even when there is no roof structure. Thus, in the case of this air bag, the rear holding point that is connected stationarily to the body of the car can be moved at the side door.
German Patent Document DE 296 11 683 U1 discloses an air bag system for a convertible vehicle, where one or more air bags are disposed in the folding roof of the convertible, with the result that the passenger is protected against impact when the folding roof is closed. The actuated air bag extends from an upper exterior of the folding roof toward the bottom such that the result is lateral impact protection for the passenger.
German Patent Document DE 198 34 666 A1 discloses an air bag equipped with two chambers that can unfold quickly at different rates when the air bag is actuated.
If, in the event of a crash, the vehicle rolls over, that is, a so-called rollover occurs, the passengers run the risk of being thrown with their heads against the relatively un-cushioned roof of the vehicle. In a passenger car designed as a convertible, there is, in addition to a so-called rollover, the risk that the passengers will make contact with the road.
The present invention deals with the problem of equipping an air bag system for a passenger car, in particular a convertible, such that the risk of injury during rollover is reduced.
The invention solves this problem, in an embodiment, by means of an air bag system with at least one inflatable air bag where the air bag is housed in a roof frame of the car, the roof frame enclosing a top of a windshield of the passenger car. When the air bag is actuated, it unfolds in a direction opposite the car""s direction of travel such that, after it unfolds, the air bag is located above the head of the driver and/or passenger of the car.
The invention is based on the idea of housing at least one air bag in the vehicle such that it unfolds above the driver""s head and/or above the passenger""s head. According to an embodiment, this air bag is housed in a roof frame, enclosing at the top a windshield of the vehicle. Due to the air bag system of the invention, a passenger also has adequate impact protection in the direction of the roof side of the vehicle even in the event of a rollover. By housing the air bag in the roof frame above the windshield, the air bag can unfold its protective effect, whereby the air bag extends itself in a protective manner between the head and road, even in the case of a convertible with the top folded down. In this case, the unfolding direction of the air bag is toward the rear and toward the top.
In a preferred embodiment there can be provided an air bag control, which is connected to a sensor, detecting a rollover of the passenger car. The air bag control actuates the air bag only when the passenger car rolls over. This measure prevents the air bag, which is housed, according to an embodiment, in the front upper roof frame, from being actuated in the event of an accident, during which it is not required per se.
To the extent that the passenger car is designed as a convertible, an embodiment is preferred in which an air bag control actuates the air bag only when a top, or roof, of the convertible is open. In such an embodiment, the air bag can be configured and dimensioned especially for the case that the top of the convertible is open, when the air bag is used. In particular it is easier to orient the direction, in which the air bag unfolds suddenly, when the top is open so that the driver""s head or the passenger""s head is not hit by the actuating air bag. Expediently the air bag control is designed in such a manner that it actuates the air bag only when the aforementioned conditions are fulfilled in total, thus for an open top and during rollover.
To avoid a collision between the unfolding air bag and the passenger""s head even in the case of a taller passenger, the air bag can unfold, upon actuation, in the opposite direction of travel and upward, according to a preferred design.
In another embodiment, the air bag can extend in essence over the entire width of the interior. The result is that for the driver and for the passenger there is one and the same air bag. At the same time the space above the driver""s head and the passenger""s head can be filled by the air bag without virtually any gap, thus reducing the risk of injury.
In another embodiment, the air bag can include at least one side wing, which unfolds downwards, upon actuating the air bag, on one side end of the air bag. After unfolding, the air bag is disposed on the side of the driver""s or the passenger""s head. In this manner, the function of a side air bag can be integrated, at least in the head area, into the air bag which is disposed on the front upper roof frame.
Another feature of the invention is the result of designing in such a manner the inflation means, provided for inflating the air bag during its actuation, that the air bag unfolds more slowly than an air bag housed in the steering wheel. Whereas in the event of a frontal collision or a side collision there is relatively little time to inflate the respective air bag in time before the impact of the head or the body, in the case of a rollover there is considerably more time before the vehicle lands on the roof. In this embodiment, the longer time is used to fill the air bag more slowly. Thus, the risk of injury caused by the filling process is reduced.
In another embodiment the air bag can also be designed in such a manner that, after unfolding, the inflated state is maintained longer, as compared to an air bag housed in a steering wheel. This embodiment is based on the recognition that a vehicle can roll over several times so that the protection, guaranteed by the air bag of the invention, is also maintained for several rollovers. Thus, in this respect, too, the air bag of the invention differs significantly from a conventional frontal air bag or side air bag that unfolds its impact protection only in the event of a single impact.
The air bag system of the invention is especially advantageous when the air bag exhibits several chambers above the head in the vertical direction. Primarily for the case that the air bag of the invention is used in a passenger car, designed as a convertible, this embodiment increases the personal protection, because the damping effect of the air bag is maintained at least to some degree even when an outer chamber is damaged during rollover due to contact with the ground.
So that the chambers fill, on the one hand, as quickly as possible upon actuation and the shape remains, on the other hand, stable when the air bag is unfolded, individual chambers of the air bag can communicate with each other by means of check valves.
Especially for an embodiment that is used in a passenger car designed as a convertible, an upper outer skin of the unfolded air bag can be made of a mechanically robust material. In this manner, the air bag material can also withstand harder collisions with the vehicle roof and in particular the road, with the result that the protective effect is improved.
There is another improvement when in the case of the unfolded air bag, a chamber, facing the driver""s or the passenger""s head, is designed softer than a chamber disposed further upwards. Thus, the protective function of the air bag can be differentiated even more, so that an area of the air bag facing the passenger interior exhibits greater impact protection for the passengers, whereas an outwardly facing area is designed harder and more robust against ground contact and the like.
According to an embodiment, the roof frame can contain a receiving space, which is intended to house the air bag and is sealed by means of the cover. This cover is mounted on a lower edge of the roof frame so as to pivot about an essentially horizontal swivel axis, running in essence at right angles to the longitudinal direction of the vehicle. The cover exhibits an open position, which is defined by an opening stop and in which the cover forms, upon actuating the air bag, an essentially horizontal bearing surface, which guides the unfolding air bag and supports the unfolded air bag. This measure can guarantee that actuation of the air bag results in optimal kinematics so that an undesired collision of the air bag with the head of the respective passenger can be avoided during the actuating process. Furthermore, in its open position the cover provides for an optimal positioning of the air bag above the respective head even when the air bag is fully unfolded so that this positioning can also be maintained especially in the event of several rollovers.
To avoid the risk of injury due to a malfunction of the air bag, a further feature provides that, for a passenger car designed as a convertible, the cover can be blocked in its closing position by means of the top of the convertible or by a component of the top when the top is closed. The cover can be opened, thus triggering the air bag, only when the top is open.
Other important features and advantages of the device, according to the invention, follow from the claims, the drawings and the related descriptions with reference to the drawings.
It is clear that the aforementioned features and those to be explained below can be used not only in the disclosed combination but also in other combinations or alone without leaving the scope of the present invention.
Preferred embodiments of the invention are depicted in the drawings and are explained in detail in the following description.